Dryer or heater with shielding means

ABSTRACT

Apparatus for drying or heating a continuous length element, and more particularly a drying apparatus in a machine for impregnating such fiber with a liquid fiber-to-rubber adhesive coating in the manufacture of tires, belting and similar products, wherein the element is rapidly dried at a controlled temperature by flame generated infrared-type heating means while (1) an adjustable shielding means controls heat flow from the heating means to the element, and/or (2) moving a gas stream rapidly over the surface of the element and shielding means to protect the heating means from the flowing gas stream against any adverse effect on the infrared radiation from the heating means and to remove heat products from the shielding means and element. The foregoing abstract is not to be taken as limiting the invention of this application, and in order to understand the full nature and extend of the technical disclosure of this application, reference must be made to the accompanying drawings and the following detailed description.

Unite Mates ll atennt Tyson et all,

[151 anaaaaa 1 ll elhififi, 11972 [54] lfllilit lr'lEilt @111 HEATER.WilTil-il SEHUHELHHNG MEANS [72] Inventors: David Z. Tyson; lEdwnr-ncl1E. llilnnter, both of Akron, Uhio; W1i11ie Herman lit est, Columbia,51C.

[22] Filed: Ang.117,19"/

[21] Appl.No.: 6 11,4188

[73] Assignee:

ii telnted 11.9.. Application lUnta [62] Division of Ser. No. 821,413,May 2, 1969, Pat. No.

[52] 111.8. 6131 Std/Alt [51] lint. Cl i .mnn 19/1111 [58] llieldollfiearellr. ..34/155, 157, 160,4 1,421; 263/3 [56] llteiferencesCited UNlTED STATES PATENTS 2,210,869 8/1940 Larson 49/74 X 2,551,9215/1951 Arsem 49/74 M 2,807,096 9/1957 Kullgren .34/45 Smith ..34/157 XFannon ..263/3 [5 7] ABSTRACT Apparatus for drying or heating acontinuous length element, and more particularly a drying apparatus in amachine for im pregnating such fiber with a liquid fiber-to-rubberadhesive coating in the manufacture 01 tires, belting and similarproducts, wherein the element is rapidly dried at a controlledtemperature by flame generated infrared-type heating means while (1) anadjustable shielding means controls heat flow from the heating means tothe element, and/or (2) moving a gas stream rapidly over the surface ofthe element and shielding means to protect the heating means from theflowing gas stream against any adverse effect on the infrared radiationfrom the heating means and to remove heat products from the shieldingmeans and element.

The foregoing abstract is not to be taken as limiting the invention ofthis application, and in order to understand the full nature and extendof the technical disclosure of this application, reference must be madeto the accompanying drawings and the following detailed description.

11) Claims, 7 Drawing Figures SHEW R W Q YIN'VENTORE \HD Z. TYSON l8EDWARD E. HUNTER BY WILLIIE H BEST ATTORNEY 3&43342 PAINTED Fma 1m SHEET(IF A asp rill

INVENTORS DAVID Z. TYSON EDWARD E.HUNTER BY WILLIE H. BEST M Z. d W

ATTORNEY EWEWH [972 SHEET M 0F Q INVENTORS DAVID Z. TYSON EDWARDE.HUNTER WILLIE H. BEST ATTORNEY H DRYER R lllllEA'IlEllt Wll'llllSlllllllELlDlNG MEANS This application is a division of copendingapplication Ser. No. 821,413, filed May 2, 1969, now U.S. Pat. No.3,590,495, issued July 6,1971.

BACKGROUND AND SUMMARY OF THE INVENTION This invention relates toheaters, including dryers, and more particularly to heaters for fibers(whether in yarn, cord, fabric, etc., form), especially such fibers tobe used in the manufac' ture of tires, belting and other rubberproducts; and to the machine for impregnating such fibers by dippinginto a liquid fiber-to-rubber adhesive and subsequently drying the same.

The rubber products industry uses various fibers for reinforcement,including rayon, nylon, polyester, fiber glass, etc., and may use now orhereafter other natural and artificial fibers. The term fiber, unlessotherwise modified, is intended to be used in its generic sense toinclude all of these fibers. This machine is adapted to process bydipping and drying any continuous length element, such as a woven fabricmade up of cord formed of fibers, a yarn made up of fibers before beingtwisted into cord and woven into fabric, etc. Dipping the yarn isusually done where application of the adhesive over the entire surfaceof the fiber is desired, such as with fiber glass; while other fibersare dipped in the fabric form. Therefore, the terms continuous lengthfiber element, continuous length element," fiber element," or element"used herein, unless otherwise modified, are each intended to cover anycontinuous length yarn, cord or fabric since each is composed of fibers.The term fabric" unless otherwise modified, is intended to cover anysuitable fabric, including square-woven fabric and including so-calledcord fabric used for tires and having a fairly open and loose weavewherein the cords form the warp and a comparatively small number of fillthreads connect the cords solely to facilitate handling.

lt is well known that before any such element made of textile materialcan be incorporated into rubber articles, especially those to besubjected to drastic conditions of flexing or bending, the fibersthereof must be prepared by coating or impregnating with an adhesivethat will bond well to both rubber and the fibers. These adhesives aredispersed, dissolved or suspended in a liquid vehicle, generally water,into which the element is clipped and subsequently dried.

Such elements have been dried by blowing hot air through a drying ovenin a relatively low temperature. Because of the low drying temperatureand the attendant low speed of operation, large capacity drying ovenshave been necessary so as to require vast expenditures of capital andlarge factory areas for operation. It has been recognized that if suchelements could be dried more rapidly, but at a controlled temperature toprevent deterioration of the fiber, the speed ofdrying could be vastlyincreased, and/or the size and capacity of the drying apparatus could beconsiderably reduced.

This invention is an improvement on the invention disclosed in the T. M.Kersker et a1. U.S. Pat. No. May 10, 1966, and entitled Method ofProcessing Tire Cords, Tire Cord Fabric, And The Like wherein infraredradiation is used to speed up the drying and many of the problems insuch element processing for rubber goods manufacture are explained insome detail to which reference may be had if desired. The dryer must beof sufficient size to dry the adhesive liquid coating sufficiently sothat the coating will not be picked off or ruptured by the rollingsupport means engaged following the drying step.

This invention is also an improvement on the copending U.S. Pat.applications Ser. No. 729,282 entitled Dryer Or Heater" filed May 15,1968, now U.S. Pat. No. 3,554,502 by Grover W. Rye and Alexander V.Alexeff and Ser. No. 729,605 filed May 16, 1968, now U.S. Pat. No.3,521,375 by Dewey C. Sanders, Jr. entitled Improved Dryer" by theaddition of a venetian'blind-type burner flame shielding means to thattype dryer with suitable modifications thereof, and the disclosures ofthose applications are incorporated herein by this reference thereto.

3,250,641, granted The present invention relates to a machine or to anap paratus for coating, heating and/or drying a continuous lengthelement, and more particularly to a machine for impregnating suchelement with a liquid fiber-to-rubber adhesive in a coating in themanufacture of tires, belting and other rubber products; or to a heatingapparatus wherein the element is heated and heat products are removedfrom said element and/or heat shielding means therefore by a gas streamrapidly moving over the surface of said element, wherein said heatproducts are evaporated water molecules for rapidly drying the elementat a controlled temperature, or heat when maintaining the heated upelement at a controlled or preselected heated temperature, or otherproducts resulting from heating this element; or to a machine used toexpose the fibers to the appropriate time and temperature conditions ata preselected temperature in the process known in the art as heatsetting, such as used for nylon to give it the desired molecularstructure and other characteristics.

An object of the present invention is to provide an ap' paratus forrapidly and uniformly heating or drying a fiber containing element at acontrolled temperature so as to manufacture a maximum quality article byminimum sized equipment.

Another object of the present invention is to provide a method of andapparatus for dipping and drying fibers at a very high temperature andspeed without detriment to the fibers or any coating thereon.

Another object of the present invention is to provide an apparatuswherein an element is heated and heat products are removed from saidelement by a gas stream rapidly moving over the surface of said elementand/or heat shielding means therefore, wherein said heat products areevaporated water molecules for rapidly drying the element, heat, orother products resulting from heating this element.

Another object of the present invention is to provide an apparatus forcoating, heating or drying a continuous length ele ment rapidly heatedor dried at a controlled temperature by flame-generated infrared-typeheating means while moving a gas stream rapidly over the surface of theelement, protecting the heating means by a shielding means from theflowing gas against any adverse effect on the infrared radiation fromthe heating means, and/or removing heat from said shielding means bysaid gas stream.

Another object of the present invention is to provide an infrared heatcontrolling shutter permitting starting and stopping of the elementbeing infrared heated without damage thereto by controlling the flow ofheat thereto.

Another object of the present invention is to provide a shutter forcontrolling the heat output of an infrared generator by closing aheat-controlling shutter to protect the element being heated whenstopped against the residual infrared heat in the generator or to reducethe infrared heat applied to the element.

Another object of the present invention is to provide a machine whereinan infrared heating means is energized and subsequently an infraredcontrolling shutter is opened to apply quickly, or to increase, infraredheat to the element being heated.

Another object of the present invention is to provide an apparatushaving a venetian-blind-type shielding means controlling infrared outputfrom an infrared generator to an element being heated and having a highvelocity gas stream traveling between the shielding means and element toremove therefrom infrared generated heat products.

These and other objects of the present invention will become more fullyapparent by reference to the appended claims as the following detaileddescription proceeds in reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS In the drawings, FIG. 11 is anelevational, schematic, vertical view (partially in section) of amachine or apparatus for coating an element and subsequently drying thecoated element in a drying tower in either a two-pass element position,as shown in solid lines, or a one-pass element position, as shownpartially in solid and dot-dash lines;

FIG. 2 is a side elevational view of two of the heating or dryingapparatuses located within the heating or drying tower in FIG. 1, havingsome parts omitted or cut away, and having opposed heating zones outsidefaces of the element in a two-pass element position;

FIG. 3 is a top plan view, taken generally along the line 3-3 in FIG. 2and turned 180, showing only the element and the gas moving means fordischarging the gas streams into and through the heating zones andsubsequently exhausting them from the apparatuses in FIG. 2;

FIG. 4 is a schematic perspective view by the fabric element of one ofthe heating apparatuses with shielding means in FIG. 2 with some partsomitted or cut away for clarity, with the controls therefor shownschematically, and with portions of the gas moving means and nozzlesshown in dot-dash lines;

FIG. 5 is a vertical sectional view through the shutter slots of theshielding means shown in closed, or more shielding, position in solidlines and in an open, or less shielding, position in dot-dash lines;

FIG. 6 is a vertical, side elevational view, taken generally alongeither line 6-6 in FIG. 2, of the fuel flow and other controls for theinfrared heaters in one of the apparatuses; and

FIG. 7 is a top plan view, taken generally along the line 77 in FIG. 2of the gas stream flow ducts, infrared panels, reflector means, centerwall, and heat shields surrounding the element.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 of the drawingsshows machine 10 for treating continuous length fiber element 12 byapplying adhesive thereto and subsequently drying the adhesive withmachine 10 including heating or drying tower 14 (taking the form ofeither a separate tower or one zone of an element processing building)having structural members 14a supporting sixteen substantially identicalheating apparatuses or dryers 16, to be described in more detailhereinafter.

Machine 10 has a plurality of element processing positions. It may beused in a two-pass element position by having element l2 follow thesolid lines as runs 12a and 12b about rolls 23, 24 and 23a to winduproll or may be used in the onepass element position by having element 12follow the combined solid and dot-dash line positions as only run 12aover rolls 23, 24 and 24a to windup roll 25. This description willprimarily relate to the two-pass element position (having both elementruns 120 and 12b) with the one-pass element position (having onlyelement run 12a) being subsequently described with respect to FIG. 3 ofthe drawings.

Although machine 10 can be used for treating any suitable fiber element12 (such as yarn, cord or fabric), a woven fabric will be specificallyused hereafter in this description with this fabric having a lengthdimension L along its direction of movement T over drive rolls 22, 23,24 and 24a or 23a; a width dimension W transverse thereto; and opposite,generally parallel faces F1 and F2.

Since each apparatus 16 is especially adapted for driving moisture outof fibers or fabric, it should be apparent that it has many other uses,such as driving moisture out of woven fabric before calendering in themanufacture of rubber goods.

Although apparatus 16 is specifically described for purposes ofillustration herein as a dryer, it will be readily apparent as thisdescription proceeds that apparatus 16 is broadly any type heatingapparatus with gas stream 42 (described in more detail hereafter)adapted for removing from element 12 any infrared generated heatproducts, whether these heat products be evaporated water during dryingor heat, such as while rapidly heating element 12 to a preselectedtemperature and maintaining it at that preselected temperature by thecooling action of stream 42 carrying away any excess heat. Infraredgenerated heat products and "heat products are defined herein to includewater vapor and molecules evaporated from element 12, heat removed fromelement 12 and/or shutter panel 62 in FIG. 4, evaporated volatiles, andother products resulting from heating element 12 with infrared heat.

Machine 10 in FIG. 1 sequentially moves fiber element 12 in traveldirection T from feed roll 21 through coating means 18, through heatingor drying tower 14 having 16 heating or drying apparatuses 16 with eachhaving infrared heating means 28, over drive roll or support means 24with fiber element l2 freely supported between drive rolls 23 and 24from the bottom or inlet in the heating zones 40 provided by tower l4,and onto windup roll 25 or to subsequent heat treating and/or otherprocessing equipment.

Coating means 18 includes tank 20 containing any wellknownfiber-to-rubber adhesive 19 dissolved, dispersed, or suspended in aliquid vehicle. Such adhesive is generally based onresorcinol-formaldehyde resins and latex in an aqueous medium.

Suitable drive means is provided for moving element 12 relative toheating means 28 through machine 10, comprising coating means 18 andtower 14, while each heating means 28 heats element 12 in its heatingzone 40. This drive means takes the form herein of suitable tensioningor support rolls 22, 23, 24, and 23a or 240 with any one or all drivenby a suitable motor driven drive or independent motors to advanceelement 12 through machine 10 and to apply suitable tension to element12. When fabric element 12 has a width W of about 60 inches, 2,00025,000pounds tension thereon may be the general operating range for differentfibers, and this tension is used for further processing thereof afterthe adhesive has been dried and for maintaining the fabric taut andplaner against lateral deflection and flapping by gas streams 42mentioned hereafter.

Roller 24 serves as a rolling support means mounted on a rotational axisextending parallel to width dimension W and located in a vertical andplaner surface (perpendicular with respect to the drawing in FIG. 1)extending through center walls 76 and between heating zones 40 of twohorizontally aligned apparatuses 16 in any given tier, such as tier T3,so that element 12 is trained upwardly in run 12a through heating zone40 of apparatus 16 in tier T3, bank B1; over rolling support roller 24;and through heating zone 40 of other apparatus 16 in tier T3, bank B2 asa second pass 12b with the outer surface Fl of element 12 being heatedin each of these heating zones respectively by the heating means 18 ofthese apparatuses 16. Vertical runs 12a and 12b of element 12 straddlingroller 24 was separated by approximately the diameter of this roller 24while going through these heating zones 40 with these heating zones 40in each tier being transversely aligned to the direction of travel ofelement 12 in opposite banks B1 and B2. Element 12 is sufficiently driedby heating means 28 in bank B1 before engaging roller 24 so that thecoating on element 12 will not be damaged or picked off by roller 24with other heating means 28 in bank B2 finishing drying or other desiredheat treating of element 12.

It has been found in practice that drying apparatus 16 in tower 14manufactures maximum quality element 12 with minimum equipment size.

Machine 10 has a plurality of apparatuses 16 therein for heating ordrying the fibers in the yarn or fabric in continuous length element 12.These are arranged in eight tiers Tl-T8, and in two banks or runs B1 andB2 so that each of 16 apparatuses 16 therein may be identified as tolocation, as to tier and bank, such as the apparatus in the lowerleft-hand corner of FIG. 1 being identified as apparatus 16 in tier T1,Bank B1. Apparatuses 16 in both banks are arranged in series along thelength of element 12 in the tiers while any two horizontal apparatuses16 in opposite banks B1 and B2 and in the same tier are arranged onopposite sides of fabric element 12 in two different runs as it passesthrough tower 14. Each apparatus 16 in each tier and bank has a widthwider than fabric element 12,

as shown in FIGS. 3, 4 and 8, to provide a proper heating or dryingaction as will be brought out in more detail hereinafter.

HEATING OR DRYING APPARATUS 116 The remainder of this application willbe directed toward the specific structure, mode of operation andadvantages of each substantially identical apparatus I6 for heating ordrying and considered either alone or in any tier or bank combination. 1The explanation hereinafter of apparatus 16 will emphasize the detailsin apparatus 16in tier T3, bank B2 even though all 16 apparatuses 16 inFIG. l are identical in construction except that the two apparatuses ineach tier are sub stantially mirror images of those in bank B2.

Each apparatus I6 includes heating means I8, preferably of an infraredemitting or radiating type, for drying the outer surface FI or F2 ofelement 12 by infrared emission portions. Although heating means 28 mayuse any suitable infrared source, such as an electric quartz tubeheating element, etc., it is preferred to use herein an infrared heater'32 having a fluid (preferably natural gas) fired flame for generatinginfrared radiation because of its economy of operation, rapid cooling,efficient heat transfer, and desirable radiating characteristics.Although any suitable infrared heater 32 may be used, one suitable formis disclosed in U.S. Pat. No. 2,775,294 granted Dec. 25, 1956 to G.Schwank and entitled Radiation Burners" wherein a gas-air mixture burnson the outer surface of plate or mat 7 in that patent to heat it toincandescence causing this surface to emit infrared radiation thenstriking and heating element 12. Such burner 32 sometimes has a metalscreen mounted about onefourth inch from this radiant surface, extendingparallel thereto, and being substantially coextensive with this surfaceserving as a reradiating screen to increase the burner efficiency and toassist in providing a uniform distribution of infrared radiant energy inthe manner well known in the art. Then, combustible gas (fluid fuel)mixed with air burns so that the outer radiating surface of plate 7 hasa visibly radiant temperature of approximately l,300-I ,600" F. with theradiation intensified by the reradiating screen. Hence, infrared heater32 has a mat or plate 7 carried flame for generating the infraredradiation emission portions for heating element 12.

Heating means 28 includes infrared heating panel 31 in FIG. 4 havingspacer blocks 33 and heaters 32 (shown schematically by crossed lines inFIG. 4) arranged in a checkerboardtype pattern within its frame 36 toprovide a planer, radiating face on panel 31 parallel to and facingelement 12 surface F1.

The intensity and pattern of radiation desired may be varied by changingthe number of heaters 32 and the number of spacer blocks 33 locatedwithin frame of panel 31 and in changing their distribution within frame30.

Each heater 32 in panel 311 is fed by gas fuel main line 34 in anysuitable manner but here shown in FIGS. ll, 4, and 6 as through suitablegas fuel controls 38, and then in parallel through fuel control valve 35and main gas line 37 to heaters 32 or through pilot line 36 for suitableignition thereof.

Gas fuel controls 38 are shown herein in series as main shutoff valve380, gas pressure regulator 38b, gas pressure gauge 38c, low pressureswitch 38d, hydromotor valve actuator 38s, vent valve 38f, blockingvalve or protector 38g, and high gas pressure switch or protector 38h.

Fuel control valve 35, or fuel input control means, is of a zerogovernor mixing type having the advantage of allowing the mixturepressure, which in turn determines the quantity of fuel flow andtemperature of the burners, to be varied by controlling the airflowvolume into the mixer. In the zero governor system, the gaseous fuelunder pressure from switch 38h is reduced to atmospheric pressure byzero governor or regulator 35a and then introduced at the throat ofventuri 35b, as shown in detail in FIG. 6 and schematically in FIG. 4,through which air is forced by combustion air blower 350 with theairflow controlled by butterfly air valve 35d, located in the airstreamflow between the blower and venturi. Hence, the

fuel gas entering at atmospheric pressure is entrained in the airflowing through the venturi in a definite fuel-air ratio with the amountof gas entrained being dependent on the amount of air passing throughthe venturi, as controlled by butterfly valve 35d, to control the energyinput to the burners or heaters 32. Also, the zero governor system hasthe advantage of providing complete control of the fuel flow, andproviding instantaneous response, all under the control of butterflyvalve 35d.

If desired, a richer gas mixture can be provided during starting byproviding a bypass line from switch 38h, around regulator 35a andventuri 35b, and directly to main gas line 37 to the burners.

The fuel for pilot line 36 is tapped off main fuel line 34 downstreamfrom gas pressure gauge 38c in FIG. 6 through pilot solenoid valve 36a,gas air mixer 36!; for the pilot burner and pivotal connections 36a inFIGS. 2 and 6 to the burner igniter pilots.

For heaters 32, the emerging fuel-air mixture from venturi 35b travelsupwardly in FIGS. 4 and 6 through main gas line 37 to burners or heaters32 through pivotal connection 37a and burner panel manifold 37b in FIGS.2, 4 and 6.

Any suitable conventional igniter and safety' features are provided.

Each gas line 36 and 37 has pivotal connections 36a, 37a therein adaptedto permit pivoting of the line components about a horizontal axis duringhorizontal movement of radiant heating panels 311 between solid anddot-dash line positions in FIG. 2, as will be described in more detailhereinafter.

Each infrared heating panel 31 heats an infrared heating zone 40 on theouter surface of element 12, such as on face F1 or F2, and the desiredaction in each heating zone M) is to rapidly and uniformly dry fabricelement 12 at a controlled temperature, This action is obtained in thepresent disclosure by rapidly and uniformly evaporating the moisture bythe infrared radiation from panel 31, and by rapidly and uniformlyremoving by mass transfer the evaporated liquid molecules and heat fromfabric element 12 in this heating zone 40 by apparatus 16. The followingparagraphs will explain this mode of operation more carefully and morespecifically.

Infrared radiation from burner 32 is an efficient method of heattransfer to provide the energy necessary to evaporate the water into itsvapor form and is much better than many other type high temperatureheating sources. The aforementioned Schwank-type infrared burner 32emits strong radiation in the absorption band for water vapor forefficiently and rapidly vaporizing the water or aqueous molecules in thecoating. The moisture within the fibers and adhesive coating is heatedand evaporated within the time period necessary to dry the adhesivecoating on the surface of the fibers while still permitting the moistureto escape therefrom before the outer surface of the adhesive is driedand/or cured sufficiently to form a skin or crust entrapping theremaining moisture.

Any suitable gas may be used, but air is specifically used herein eventhough the generic term gas" is used wherever appropriate since anysuitable gas may be used. A gas moving means moves gas stream 42 withrespect to and between outer surface Fl of element 12 and shutter slats65 of shielding means 62 through heating zone 40 in FIGS. 2 and 4: (l)during infrared heating of surface F1 for removing infrared generatedheat products from surface F1, and (2) at all times (both when shutterslats 65 are open and closed) for removing infrared generated heatproducts from shutter slats 65. This gas stream 42 is a desirable partof this structure for removing the heat products and for preventing burnup or heat deterioration of element 112 or shutter slats 65, althoughstream 42 may be omitted and not necessary for lower heat intensityconditions with shutter slats 65 providing effective shielding ofelement 12 and adequate protection against damage. These removed heatproducts may take the form of: (1) heat removed from surface F1 and/orshutter slats 65 for controlling the temperature of surface Fll and/orshutter slats 65 by a cooling action, and/or (2) liquid molecules, suchas water molecules, evaporated by the infrared and removed by gas stream42 by mass transfer by scrubbing surface F l with stream 42 so as torapidly dry element 12 at a controlled temperature. Stream 42 is arapidly flowing river of gas blowing at and traveling along and oversurface F1 being heated or dried by the infrared and traveling along andover shutter slats 65. With fabric element 12 saturated with water basedchemicals 19, a fast rate of drying of element 12 to remove the water ishighly desirable. Fast drying results in minimum equipment size,improved control of drying conditions, and improved quality of element12. The evaporated liquid molecules carried away by stream 42 include,of course, not only water molecules but molecules of any volatilematerial. The rate of drying is increased by removal of liquid moleculesfrom surface Fl to allow better penetration of infrared energy and bythe efficient mass transfer of water molecules to the gas by a scrubbingor vacuuming action of surface F1 by flowing stream 42. Flowing stream42 also removes convectional heat from drying zone 40 and from fabricelement 12 so as to provide a rigid control of the temperature of thefabric element so that it will not exceed the safe limit. The gas instream 42 is cool enough to cool element 12 as it passes across it. Thisis a peculiar problem to a fabric, such as nylon, some types of whichmight be damaged if the temperature exceeded 250 F. Not all objectsdried require this close temperature control by cooling; for example,ceramics, painted metal parts, etc., preferably pick up as much heat aspossible and cooling is not desired since cooling is a detriment toefficient operation. It should be apparent that velocity of stream 42will affect the extent of scrubbing action and rate of drying and theoverall quantity of air flowing in stream 42 will affect both rate ofdrying and heat removal. Preferred condition of the gas in stream 42 isa relatively dry and cool gas, such as air at ambient conditions. Thecool gas will have a greater capacity for heat pickup, and the dry gaswill pick up the moisture and other evaporated molecules more quicklyand is more transparent to infrared radiation from panel 31. Moistureladen gas interferes with the transmission of infrared rays (because itabsorbs this infrared radiant energy) and interferes with efficientdrying and heat transfer. Therefore, if gas stream 42 is heavily ladenwith moisture, it may substantially prevent transmission of the infraredrays from panel 31 to surface F1 and may serve as an insulating layerover surface F 1 to prevent removal of heat and water vapor. Hence,recirculation of the gas in stream 42 would not be desirable because itwould be hotter than desired so could not pick up more heat and couldnot cool element 12, and might well be saturated with evaporatedmolecules, such as water molecules, which would interfere with infraredtransmission and pickup of evaporated water molecules. Hence, gas stream42 permits infrared heaters 32 to operate at their most efficienttemperature, is located as close as possible to fabric face F1 for fastdrying, and still permits accurately controlling the surface temperatureof element 12 to prevent damage thereto. Note that the infraredradiation from heaters 32 strikes heating zone 40 to provide drying atthe same time as gas stream 42 scrubs the heating zone. This actionprovides most rapid drying with minimum size equipment.

The aforesaid gas moving means includes gas discharge means fordirecting gas stream 42 as a gas layer or gas curtain generally alongand over surface F l in heating zone 40 to provide the aforedescribedscrubbing action. Since the air of the condition described in thepreceding paragraph is preferred, relatively cool, dry air at ambientconditions is drawn in by motor driven, discharge, fresh air or inletfans 44 in FIG. 1 through inlet duct 46 in FIGS. 1, 2 and 3 to be forcedthrough nozzle duct 48 and out discharge nozzles 50 in FIGS. 2 and 4 toform gas stream 42 for apparatus 16. Gas discharge nozzle 50 has arectangular outlet having its length 50L in FIG. 4 many times greaterthan its width 50W.

Discharge nozzle 50 is preferably mounted so that length dimension 50Lis generally parallel to surface Fl of element 12 in heating zone 40 andwidth dimension 50W is generally perpendicular to surface Fl with nozzle50 directing its discharged gas stream portion generally along surfaceF1 in heating zone 40 from the lower edge of this heating zone forremoving infrared generated heat products therefrom. It should beapparent that scrubbing action and heat removal will be obtained byhaving the discharged stream from nozzle 50 directed transverselyacross, longitudinally with (in cocurrent flow along run 12a), orlongitudinally against (in contraflow along run 12b) travel direction Tof element 12. Directing stream 42 across travel direction T (acrosselement 12 width W) would not be desirable because stream 42 would notuniformly hit with the same velocity, impact and temperature eachportion of width W of fabric element 12 so that the fabric would not beuniformly processed across its width. Nozzle 50 may be mounted near oneedge of heating zone 40 with its length dimension 50L generally parallelto, or extending across, width dimension W of fabric element 12 with airstream 42 directed in heating zone 40 generally uniformly across thewidth of and along the length of movement T of element 12 either in thesame direction (in cocurrent flow) or the opposite direction (incontraflow) to the movement T for generally uniformly removing liquidmolecules over width W of element 12 to give width W uniform processing.It has been found desirable to mount nozzle 50 at the bottom of heatingzone 40, as shown in FIGS. 1, 2 and 4, so that gas stream 42 is directedupward so that the natural convection will help move gas stream 42toward gas exhaust vent 56.

Nozzle length dimension 50L should be at least as wide as widthdimension W of fabric element 12 so that gas stream 42 will uniformlyeffect each increment of the fabric across its width as it travels indirection T. Dimension 50L should be preferably greater than fabricwidth W so that the lower velocity components in gas stream 42 emergingfrom the lengthwise ends of nozzle 50 do not travel across surface F1and a more uniform velocity layer of gas in stream 42 travels along thelength of element 12.

It is desirable to provide a generally uniform quantity of gas flowingover each portion of fabric element width W in heating zone 40 forgenerally uniformly removing the heat products across this width W, withsuch heat products being evaporated liquid molecules and heat formaintaining a generally uniform temperature across fabric element widthW in heating zone 40 since drying and heat removal are directlyproportional to the quantity of gas flowing in stream 42 and since thescrubbing action is proportional to the velocity of flowing stream 42.This uniform distribution of gas across width W may be obtained eitherby carefully designing nozzle 50 and maintaining its width 50W constantwhile providing certain desirable gas turning vanes and baffles withinnozzle duct 48 and closely adjacent nozzle 50 to control thedistribution of gas flow to nozzle 50, or by making nozzle 50adjustable.

It is also desirable to have gas stream 42 directed toward surface F lto increase the scrubbing action and heat transfer action. Directing gasstream 42 toward and causing it to impinge against surface Fl has theadvantage of increasing the scrubbing and heat transfer action whenstream 42 strikes surface F1 a glancing blow and of protecting againstadversely af fecting the flame generated infrared radiation fromflame-type infrared burners 32, as mentioned in the next paragraph.Water vapor in a boundary layer on surface F 1 will also interfere withthe transmission of infrared rays thereto and removal of convection heattherefrom so that striking surface F1 by stream 42 is desirable to breakup this boundary layer.

If gas stream 42 strikes the radiating face of burners 32, it mayadversely affect the flame generated infrared radiation from thisflame-type infrared burner 32 by either adversely affecting the flame orby excessively cooling the outer infrared radiating surface on plate 7in the aforementioned Schwank patent. The flame may be adverselyaffected by being blown out, sucked off the outer radiating surface ofradiating plate 7 in the Schwank patent by the venturi effect underBernoullis Theorem, reduced in size, or at least adversely affected toreduce substantially infrared radiation output from the radiating platesurface by preventing proper flame combustion.

The gas moving means in each apparatus 16 also includes gas exhaustopening 56 having at least (and preferably much greater) flowcross-sectional area than the flow cross sectional area of gas dischargenozzle 58 and being similarly oriented with respect to surface Fl ofelement 112 but located on the downstream side of gas stream 42 fromheating zone 40 and discharge nozzle 50. Preferably, the mouth of eachexhaust opening 56 is larger in dimension 50W than discharge nozzle 58since gas stream 42 to be exhausted has swelled in volume since it haspicked up heat and moisture so that a larger volume has to be exhaustedthrough gas exhaust opening 56. Apparatus 16 in FIGS. 1 and 2 hasexhaust opening 56 exhausted by exhaust fans 60 in FIG. ll through ducts58.

Although the present invention is illustrated with gas stream 42 usedtherein, it will be readily apparent as the description proceeds thatmany of the advantages of the present invention are obtained when gasstream 42, gas nozzle 50 and exhaust opening 56 are omitted, so that theinvention in its broader aspects does not include such structuretherein.

Shielding means 62 is a shutter panel shown in FIGS. ll, 2, 4 and 7located at all times in each apparatus 16 between infrared emittingheating means 28 and heating zone 40 in all of the different shieldingpositions assumed by its venetian-blindtype shutter slats or blades 54.This shielding means 62 comprises a venetian-blind-type blind 63 havingslats 65 spaced along the length of element 112 in direction of movementT and extending generally transverse thereto along element widthdimension W. Shielding means 62 operates and is constructed very similarto a conventional venetian-blind or shutter made up of individual, thin,generally rectangular slats or blades 65 interconnected together butmovable or adjustable simultaneously to any selected angle to regulatethe light, wave or emission portions; and air or gas stream portionspassing therethrough by use of some suitable'type actuator, here shownas including cylinder-piston unit 78 in FIG. 4. Each shielding means 62includes two base members 64 in each apparatus 16 extending generallyvertically and parallel in FIG. 4. A plurality of shutter slats orblades 65, here shown as 25 in number in each panel 62, each havecoaxial rods 65a connected to the opposite ends of the plate portion 65bof each shutter slat 65 in turn each rotatably supported in plainbearing 64a in base member 64 as plain bearing connections to permit anynecessary oscillation of each shutter slat 65 in its base members 64about the axis provided by coaxial rods 65a. These rods 650 arepreferably drill rods, and no lubrication is required in these bearingconnections in view of the similarity of materials in rods 65a and stealbase member 64 in spite of the large variation in temperature to whichthey are subjected.

Each apparatus 16 includes apparatus subframes 16a and 16b detachablysecured by nut-bolt units i160 and 16d respectively to structuralmembers 14a of drying tower 14. Subframe 16a rigidly carriesrespectively heating means 28 and burner controls thereof with shutterbase members 64 of associated shutter panel 62, and subframe ll6brigidly carries inlet gas stream duct 46 with exhaust duct 58 ofapparatus 16 therebelow.

Each shutter slat 65 is formed of any suitable material and has anysuitable construction. It has been found desirable to make plate portion65b of aluminized steel, since it maintains for a long time itsreflectivity of infrared radiation in use and has good heattransmissibility; and with a plurality, here shown as three,longitudinally extending cold work breaks 65c in FIG. spaced along theshutter slat width to make the shutter slat more rigid lengthwise and toprevent sag thereof when subjected to extreme heat conditions or intenseinfrared radia tion.

The common actuator for all of the venetian-blind slat 65 in shutterpanel 62 in FIG. 4 includes a bellcrank arm 66 secured to the outer endof one of the rods 65a on each shutter with the distal ends of thesearms 66 pivotally connected to a common connecting rod 67 pivotallyconnected by cleavis 68 to the upper end of piston 70p in fluid-actuatedcylinder-piston unit 70 so that moving piston 76;; to the position shownin ill FIG. 4 in its stationary cylinder 70c, will move shutter slats 65to an open (one of the less shielding) position 620 shown in FIG. 4 andin dot-dash lines in FIG. 5 and lowering piston 76p will move the slats65 to the solid line position 620 in FIG. 5 as a closed, or one of themore shielding positions. Hence, vertical movement, or reciprocation, ofconnecting rod 67 in FIG. 4 will open or close the individual shutterslats or blades 65 so as to control the total effective aperture area ofinfrared transmission in both directions by infrared transmission zones,apertures or orifices 69 between heating means 28 and heating zone 40 inits respective apparatus 16.

Now, it should be apparent that shielding means 62 in FIG. 4 interceptsin a shielding position the travel or at least some of the portions hererecited between infrared emitting heating means 28 and outer surface F1on element 112 in heating zone 4-with these intercepted portionsincluding infrared emission portions traveling from right to left inFIG. 4 from heating means 28 to heating zone 48 between shutter slats 65and including gas stream portions able to travel from left to right inFIG. 4 from heating zone 40 toward heating means 28 between shutterslats 65. Piston 70p of the shielding control means is adapted to moveslats 65 between a plurality of positions, including more shieldingpositions and less shielding positions, between a fully closed position620 shown in solid lines in FIG. 5 and an open position 62c shown indot-dash lines with the less shielding positions permitting the travelof more of any of these portions through transmitting zones or apertures69 between heating zone 40 and heating means 28. In any of the lessshielding positions, infrared emission portion transmitting zones 69 arelocated between adjacent shutter slats 65; are of generally uniformwidths; extend across element 112; permit uniform infrared heating ofelement 12 across width W of element 12; and are at least partially, orfully, closed in each of the more shielding positions.

These adjustable shutter slats 65 are adapted for quick opening andclosing. In an open or partially open position, shutter slats 65 allowthe radiant, infrared heat to pass through shieldingmeans 62 fromheating means 28 to element 12 and heating zone 40, while keeping thecooling and drying gas stream 42 confined close to element 12 and awayfrom flametype radiant heating means 28 so as not to cool, or otherwiseadversely affect, heating means 28. In closed position 620, shutterslats 65 intercept and prevent the infrared heat from heating means 28from reaching element 12 in heating zone 40 while the cooling and dryingair in stream 42 continues to flow over element 12 and shutter slats 65to avoid heat damage to both slats 65 and element 12, such as mightoccur when element 12 stops. This heat protection is obtained eventhough infrared heating means 28 may still be emitting the same highinfrared output. It should be apparent that shutter slats 65 may bemoved to intermediate positions to control the intensity and amount ofheat reaching element 12 heating zone 40 even when heating means 28 ismaintaining a constant and high infrared emission rate. Hence, thevarious positions of slats 65 are able to change almost instantaneouslythe flux density, or infrared energy, striking element 12 in heatingzone 40. The aforedescribed infrared emission portion transmitting zones69 between the shutter slats 65 act as infrared energy transmissionapertures 69 rapidly varied in size and area by repositioning of piston70p to provide the same infrared energy transmission control as obtainedfor light transmission by a conventional venetian-blind.

If gas stream 42 is moving at too high of a velocity or if too large ofa quantity of gas is flowing in stream 42, the infrared radiation fromflame-type burner 32 may be adversely affected, as aforedescribed.Reducing and eliminating this adverse eifect has been achieved byinsertion of shutter panel 62 as a deflecting screen in FIG. 2preferably secured to subframe ll6a; mounted between infrared heaterpanel 31 and fabric element ll2 to be dried; extending generallyparallel to fabric surface F1 in heating zone 40; and extendinggenerally parallel to the direction of movement T of fabric element 12.Broadly speaking, this shutter panel 62 is a burner shielding meansintercepting the infrared rays from the emitting surface of infraredpanel heating surface 31 to element surface F 1 in heating zone 40 forpreventing adversely affecting the flame generated infrared radiation,such as by shielding the flame on infrared heaters 32 from blowout, bygas stream 42 while permitting infrared rays from heaters 32 to strikesurface F1 in heating zone 40 for drying.

Gas stream 42 and screen 64 coact to provide numerous advantages.Velocity of stream 42 discharging from nozzle 50 may be as high as 6,800feet per minute without adversely affecting infrared radiation fromburners 32. Also, a portion of the gas layer in gas stream 42 movesacross the fabric side of panel 62 while heaters 32 are emittinginfrared heat so as to reduce any infrared elevated temperature of panel62 so as to prolong its useful life, and to minimize warping andoxidation thereof. Higher velocity gas stream 42 substantially increasesthe speed of uniform drying while still maintaining element 12 at acontrolled temperature. The fabric quality produced is still better andis produced on smaller sized equipment. Hence, a great superiority isobtained by using panel 62. Gas stream 42, traveling between fabricelement 12 and panel 62, at high velocity accelerates the drying whilepanel 62 diverts this gas from the flame generated radiating surface onburners 32 to allow efficient burner operation. The higher velocity gasremoves water vapor more quickly to greatly increase the dryingefflciency while still maintaining fabric temperature more uniformacross dimension W and at a lower temperature.

Also, this fast drying action makes possible production of cord fabricwithout a webbed condition, wherein the adhesive liquid forms a hardenedfilm across the open mesh of the fabric securing adjacent cordstogether.

If gas discharge nozzles 50 are properly designed to keep gas stream 42flowing in a laterally compact and flat stream close to element 12,shutter panels 62 will not need to provide much gas stream shieldingeffect for heating means 28.

Two panels 62 in any given tier, such as tier T3 in FIGS. 1, 2 and 7,has secured to each vertical base members 63 in FIG. 7 a reflector plate74, four in number for each tier, straddling the edge of fabric element12, and preferably formed of aluminized steel to maintain theirreflectivity. The inner ends of four reflector plates 74 are secured tocenter wall 76, preferably made of suitable infrared reflecting materialcapable of withstanding high operating temperatures, such as aluminizedsteel, Maranite (pressed asbestos board) etc. In each tier, such as tierT3, two heat shields 77 in FIG. 7 straddle heating zones 40 and aresupported by hooks on subframes 16a. These four reflector plates 74 formtwo generally parallel reflector means extending along direction T ofrelative movement of element 12 and straddling the opposite edges ofelement 12 for heating those edges in heating zones 40 more uniformly byinfrared radiation by reflecting the infrared radiation back onto theseedges of the fabric, since these edges would not otherwise getsufficient radiation since they are close to the edge of panels 31.Hence, these reflector plates assure uniformity of infrared radiationover full width W of fabric element 12 by capturing the infraredradiation that would otherwise escape laterally through the gap betweenpanels 31.

Flow ducts or flow channels 78 are formed, one duct outside each side offabric element 12, for conveying the gas in each gas stream 42 as an aircurtain from its discharge nozzle 50 to its exhaust openings 56. Eachgas flow duct 78 extends along the length of element 12, has element 12surface F1 or F2 as one wall thereof, and is mounted to receive gasstream 42 from discharge nozzle 50 for keeping gas stream 42 flowingover and close to this element surface and for discharging the gasstream 42 into discharge opening 56 for exhausting from tower 14.

Each vertically extending flow channel or duct 78 for gas stream 42 isformed by surface F1 or F2 of element 12, two reflector plates 74 andelement 12 side face of panel 62 with these two ducts 78 each beinggenerally trapezoidal in cross section, generally parallel, andstraddling element surfaces Fl or F1 and F2. Each panel 62 is preferablysecured in FIG. 2 against lateral movement relative to gas dischargenozzles 50 and element surfaces F1 and F2 in heating zone 40, andtherefore will not move with panels 31 as they are retracted to thedot-dash line positions in FIGS. 2 and 4 during infrared shutdown.Hence, there is a constant geometry between panels 62 and element 12 forcontrolling the thickness of gas streams 42 straddling element 12, whichgeometry will not change even though panels 31 are movable between thesolid and dot-dash line positions in FIG. 2.

Each duct 78 plays an important part during travel of its stream 42 fromdischarge nozzle 50 to exhaust vent 56. Duct 78 guides, holds laterallycompact and prevents lateral dispersion of stream 42 to maintain theflow action of stream 42 in direction T along element 12 and towardexhaust vent 56 while keeping stream 42 in close contact with elementface F1 or F2.

Although two ducts 78 and four reflector plates 74 have now beendescribed for two apparatuses 16 in FIGS. 2 and 7 for convenience, itshould be apparent that a single duct 92 straddled by only two reflectorplates 74 give the same advantages for a single apparatus 16.

HEATING MEANS AND SHUTTER PANEL CONTROLS IN DRYING APPARATUS 16 thereto;(2) quick control of the heat from the infrared generator 28 to webelement 12 by either (a) closing slats 65 to position 620 to protectelement 12 when stopped against the residual infrared heat in infraredgenerating heating panel 31 or to reduce the infrared heat applied toelement 12 in heating zone 40, or (b) having the infrared heating panel31 on and subsequently opening shutter panel 62 to position 620 to applyquickly, or to increase, infrared heat to element 12; and/or(3),maintaining stream 42 of high velocity gas traveling in contact withheated surface F1 of element 12 and prevented by shutter slats 65 fromblowing out or cooling the flame on the gas-fired infrared heating panel31.

A plurality of heat output control means are provided for controllingthe infrared heat output from heating means 28 to element 12 in heatingzone 40. This means includes the fuel input control means provided bybutterfly valve 38d in FIG. 4 of fuel valve 35; flowing gas stream 42adjusted by piston cylinder unit 117 controlled by cam 132a; shutterslats 65 adjusted by piston-cylinder unit controlled by cam 130a;piston-cylinder unit 1 15 for moving infrared panel 31 between the solidand dot-dashed line positions; etc.

Now, there will be described the operation'of control panel forapparatus 16in FIG. 4 in this sequence: (1) single apparatus 16 in tierT3, bank B2 having infrared heating occurring with shutters slats 65 inFIG. 1 in their open, dot-dash line position 620 in FIG. 5 and withelement 12 traveling at maximum speed in direction T and then (a)element 12 is stopped and heat to element 12 is reduced, (b) the overtemperature control occurs to reduce the heat output from heating means28, (c) element 12 is started to move in direction T and heat is appliedthereto, and (d) travel speed of element 12 is in direction T at a lowerspeed, or never reaches the original high speed travel in thatdirection; and (2) the sequence of operation and programming of multipleapparatuses 16 at different tiers T and banks B to work in a mannercoordinated by speed and also to provide different temperaturecombinations or heat intensities on element 12.

FIG. 4 shows control panel 100 for apparatus 16 in tier T3, bank B2 insolid line position when element 12 is traveling at high speed indirection T and infrared heat output from heating means 28 is at amaximum. Now, valve actuating solenoids 101, 103, and are not energizedsince high temperature switch trolled 107 and stop switch 109s are open,and speed conswitch box 109 has deenergized line 111. Deenergizedsolenoids 101, 103, and 105 have respectively moved their respectivesolenoid controlled four-way valves 101a, 103a, and 105a to the positionso that the fluid pressure in air line 113 has moved piston 70;; foractuating shutter slats 65, piston 115p for actuating heating panel 31,and piston 117p for actuating butterfly valve 35d to the solid linepositions shown with the shutter slats 65 in their fully openedposition, heating panel 31 in its advanced and solid line positionclosest to element l2, and butterfly valve 35a in its fully openedposition to provide maximum fuel-air mixture to heating panel 31. Then,heating panel 31 has its maximum infrared output and maximum infraredemission occurs through shutter panel 62 to provide maximum infraredintensity in heating zone 40.

When the driving action of drive rolls 22, 23 and 24 in FIG. 1 onelement 12 is shut down so as to stop the relative movement of element12, it is important in each of the 16 apparatuses 16 in tower 14 toimmediately shut down infrared radiation from heating means 28 in allapparatuses 16 and to continue the flow of gas stream 42 undiminished,by continued energization of the gas moving means, so as to relative lymove gas stream 42 with respect to and over surfaces F1 and F2 ofelement 12 in all heating zones 40 so as to prevent residual heat fromheating means 20 from raising the temperature of and damaging element12. This action will be described herein for only one apparatus 16 sincethe 16 in tower 14 are simultaneously controlled in the same manner.Here, inlet fans 44 and exhaust fans 60 in FIG. 1 operate continuouslyso as to run when fabric element 12 is stopped as well as when it isbeing driven in the direction T during fabric processing, heating ordrying.

When element 12 stops traveling in direction T, the heat output controlmeans includes means responsive to stopping of element 12 for cuttingoff the infrared heat output to element 12 in heating zone 40. Then, anyone or all of these actions can occur to reduce heat output: (1) closingof shutter panel 62 to its solid line position 62c in FIG. 5, (2)retracting burner panel 31 to its dotdash line position in FIGS. 2 and4, and/or (3) cutting off the fuel to burner panel 31 by closingbutterfly valve 35d.

Speed controlled switch box 109 may be of any suitable type but is shownschematically here as having a follower 109a driven by element 12 inturn rotating a centrifugal-fly-weights type speed governor typemechanism adapted to move endwise upon change in speed control shaft109C of switch box 109 adapted to trip different switches within switchbox 109 for different speeds of element 12 for energizing in differentmanners or sequences from line L1 the outlet cables 118a-l10p leadingrespectively one to each of the 16 apparatuses 16 in FIG. 1 and adaptedto close switch 109s when element 12 stops.

When element 12 stops, closed switch 10% in FIG. 4 forms Circuit No. C1from line L1 through normally open switch box 109 actuated stop switch109s now closed; lines La, 1241 and 111 to circuit terminal C to begin a"Reducing Heat Output Sequence described hereafter; in parallel throughvalve actuating solenoids 101, 103 and 105 and normally closed solenoidcontrol switches 101s, 103s, and 105s; lines 122 and Lo; and Line L2.Energizing solenoids 101, 103 and 105 will respectively cause piston 70pto move downwardly until shutter slats 65 are in their fully closed andsolid line position 620 in FIG. 5, piston rod 115 to move to the rightin FIG. 4 to move burner panel 31 to its dot-dash line or retractedposition, and piston 117p to move to the right in FIG. 4- to closebutterfly valve 35d to reduce the infrared heat radiation in heatingzone 10 in three different ways. Any one, two or three of these ways maybe deactivated and caused not to occur, or if it has occurred, to returnto its full heating position by selectively opening control switch 101s,1035 and/or 105a to deactivate its respective controlled solenoid (101,103 and/or 105) so that its respective piston rod (70,0, 115;) and/or117p) will return to the solid line position shown in FIG. 4. Hence, theoperator has the opportunity of electing which one, two, or three ofthese events will occur. This ends the description of the Reducing HeatOutput Sequence." For example, if travel of element 12 is expected to beinterrupted only momentarily, or even for a considerable period of time,it may be desirable to only close shutter panel 62, but to permit burnerpanel 31 to remain in its advanced position and. supplied with maximumfuel-air mixture by opening only switches 103s and 1055. Then, the heatoutput control means comprises only means for operating the shieldingmeans 62 to intercept the travel of more of the infrared emissionportions in the closed, or more shielding, position 620 and this actionchanges the heat output to heating zone 40 independently of the residualheat in heating means 28 and with gas stream 42 keeping shutter slats 65and element 12 sufficiently cool to prevent heat damage thereto. This isa preferred mode of operation in continuous processing of element 12since stopping of element 12 is usually not for an extensive period of'time, and this mode of operation permits the full infrared output ofheating panel 31 to be available immediately to element 12 uponreopening shutter slats 65.

Heating panel 31 is moved between the solid and dot-dash line positionsin FIGS. 2 and 4 by cylinder-piston unit comprising cylinder 115apivotally connected at 115d in FIG. 2 to subframe 16a and having thefree end of its piston 115p secured pivotally by clevis 15fto arm 31asecured to and projecting outwardly from the back of burner panel 31 andbraced thereto by diagonal brace 31b. Two parallel links 121 arepivotally secured at their lower ends to arm 31a and at their upper endsto subframe at spaced points so that burner panel 31 is swung through aslight arc by a parallelogram motion in moving between solid line anddot-dash line positions by cylinder-piston unit 115. If burner panels 31are not to be retracted in some or all of the apparatuses 16, the burnerpanel selected to remain stationary can be retained in the advanced andsolid line position by clamping arm 31a in the burner panel advancedposition on subframe 16a and disconnecting its valve 103a from pressureline 113. Hence, the heat output control means comprises a heating meanspositioning means for moving heat output panel 31 of heating means 28between a retracted position and an advanced position relative toheating zone 40 for controlling the heat output to said heating zone 40.

If shutter slats 65 are shut and heating means 28 is emitting high heat,there is possibility of overheating the apparatus, including shutterslats 65. Then, the heat output control means includes shutoff means forburner or heating means 28. This includes high temperature or overtemperature limit switch 107 having heat responsive element 107a, suchas a high temperature bimetal heat responsive element, located betweenshutter panel 62 and heating panel 31 so as to be responsive to a givenhigh temperature condition thercbetween. The high temperature of element107a will close switch 107 to form Circuit No. C3 from line L1 to lineLb, line 120, normally open switch 107 now closed, and circuit junctionC to go through the aforedescribed Reducing Heat Output Sequence." Heatresponsive element 107 is located in a heat chamber formed by shutterpanel 62, heating panel 31, and straddling heat shields 77 in FIG. 7. Asmentioned earlier, there is an advantage to just closing shutter slats65 and not turning off heating panel 31. To gain this advantage, thishigh temperature, or overtemperature, limit switch 107 is set not toclose until about 30 minutes has elapsed with this closed shuttercondition.

When element 12 is stationary, such as in the beginning of operation ofmachine 10, and has not started to travel in direction T, it isdesirable to have full heat available at heating panel 31 before shutterslats 65 open so as to provide immediately full heat to eliminate 12 assoon as it begins to move and shutter slats 65 open. After Circuit No.C1 formed, the Reducing Heat Output Sequence" occurred with energizationof solenoids 101, 103 and 105. Now, if switches 103s and 105s areopened, shutter slats 65 will remain in their closed position, butheating panel 31 will advance to its solid line position and butterflyvalve 35d will open so that heating panel 31 will have high infraredoutput even though closed shutter blades or slats 65 protect stationaryelement 12. As element 12 gets up to speed, stop switch 109s opens tobreak Circuit No. C1 to open shutter slats 65 and full infrared heat isimmediately applied to element 12 so that switches 103s and 105s canthen be closed to make ready the circuitry control for reforming thesafety Circuit No. C1 or No. C3, if necessary. Hence, the heat outputcontrol means here includes means for providing infrared heat output byheating means 28 while element 12 is stationary and shielding means 62is in a more shielding position, such as a closed position 62c, andincludes means for moving shielding means 62 to an open, or lessshielding, position upon movement of element 12 in direction T so that aquick increase in heat exposure time is obtained by having heating means28 energized before shielding means 62 moves to this less shielding, oropen, position,

Pushing emergency stop button PB will cut off all heat to element 12 toenergize solenoids 101, 103 and 105 by forming Circuit No. C5 from lineL1 to normally open push button PB; lines La, 124 and 111; andcircuitjunction C to go through the aforedescribed Reducing Heat OutputSequence."

Although control 100 described heretofore and illustrated in FIG. 1 willwork satisfactorily, there may be added to control 100 a modulatingcontrol for shutter panel 62 and fuel input by butterfly valve 38d usedto provide multistep control of the infrared output to heating zone 40for each apparatus 16 and to provide various combinations of heating bythe different apparatuses 16 at different speeds of element 12. Theaddition of this modulating control includes adding in control panel 100cables 126 and 128, stepping switches 130 and 132 and their respectivelydriven cams 130a and 132a, and adding more wires to cables 118a-118pwhere necessary.

But before describing this modulating control, it is preferred tobriefly describe the relationship of control panels 100 (one controlpanel 100 being shown in FIG. 4 for apparatus 16 in tier T3, bank B2 forall of the control panels 100 in the plurality of apparatuses 16 indrying tower 14. Each apparatus 16 has control panel 100, substantiallylike control panel 100 shown in FIG. 4. Power lines La, Lb and Lc inFIG. 4 extend vertically through drying tower 14 with each control panel100, one for each apparatus 16, having its own lines 124, 120, and 122,respectively, connected thereto in the same manner as shown in FIG. 4.Only one speed controlled switch box 109, follower 109a, switch 109:,and emergency stop button PB is used but the sixteen apparatuses 16 eachhas its own individual cable leading thereto from the group of sixteencables 118a-118p in FIG. 4 connected to line 111 in its own controlpanel 100. Hence, all sixteen control panels 100 are under the controlofthe same speed controlled switch box 109.

Each of the sixteen control panels 100 has a similar modulating control(varying in wiring) for the shutters and fuel input but with eachsecured to different contacts within switch box 109 by its respectivecable 118a-118p. For example, the modulating control in FIG. 4 includescable 118a branching out into power line 111 earlier described and twocables 126 and 128, each having a plurality of electrical lines therein,and operatively connected to energize respectively conventional type,electrically actuated, solenoid driven, rotary stepping switches 130 and132 (commonly called a finder type or selfinterrupted type rotarystepping switch), respectively, rotatably driving cams 130a and 1320into different travel impeding relationships respectively with shoulders70s and 117s carried respectively by pistons 70;: and 117p to establishdifferent piston stopping positions short of the shutter panel 62 closedand butterfly valve 35d closed positions when the fluid pressure inthese respective cylinders urge them toward these closed positions. Itshould be apparent that any one or more preselected intermediate shutteropen or butterfly valve open positions may be prechosen by merely thehookup provided between the component lines or wires of cables 126 and128 with the many speed control switches in box 109 through cable 118aand the different stepping positions of stepping switches 130 and 132.Also, since each stepping switch 130 and 132 has a plurality of arcuatepositions able to be preselected by actuation of switches in switch box109, a plurality of different intermediate positions are availablebetween fully opened and fully closed positions for shutter panel 62 andbutterfly valve 35d and the position of the slats 65 in shutter panel 62can be selected independently of the position of butterfly valve 3511.Also, suitable time delay can be provided where necessary in switch box109 for some cables 118a-118p so that stepping switches 130 and 132 willreach their final selected positions before solenoids 101 and energizeand moved their controlled pistons into engagement with stops 70s and117s.

If stepping switches and 132 are used, it may be necessary to restoretheir cams 130a and/or 132a to their noninterfering position withrespect to travel of piston 70p and/or 117p whenever the control wantsshutter panel 62 or butterfly valve 35d fully closed by energizedsolenoid 101 and/or 105. For example, when Circuit No. C1, C3 or CS wasformed, as aforedescribed, energization of these solenoids 101 and 105and full closing of shutter panel 62 and butterfly valve 35d weredesired.

This action may be accomplished by having conventional rotary switchhoming units on rotary switches 130 and 132 energized from thenenergized line 124 to line L2 to return rotary switches 130 and 132 to 0position where cams 130a and 132a do not interfere with these pistontravels. When switch 107 is closed, shutter panel 62 and stop switch109s will be closed when element 12 is stopped.

This modulating control for the shutters and fuel input can be set inseveral different ways for each apparatus 16 to satisfy the drying andprocessing needs for element 12, such as when element 12 is anadhesively coated fabric. First, shutter slats 65 and butterfly fuelvalve 35d may be caused to assume different positions at differentelement 12 speeds between stopped and full speed travel in direction T,earlier described. Hence, the heat output control means thus includesmeans responsive to the slowdown of element 12 from high speed forreducing the heat output to heating zone 40 in that particular apparatus16. Hence, the infrared passageway openings 69 in shutter panels 62 andthe fuel sent to the heating means can be modulated as a function of thespeed and the heat requirements of element 12 when it passes theparticular drying apparatus 16. Second, any selected combination ofheats from the sixteen different apparatuses 16 can be made at eachspeed with different combinations available for different speeds. Forexample, all of the apparatuses 16 can be turning out the same uniformhigh or low heat; some may be shut off; some may be operating at maximuminfrared heat output and others at minimum or some intermediate output;etc. For example, in FIG. 4, cable 118:: could provide electrical linesto adjust the heat output by heating means 31 by forming Circuit No. C7from line L1 to the proper closed switch or switches in box 109, cable118a to line L2; (1) through stepping switches 130 and 132 to move cams130a and 132a to the desired intermediate heat output position, and (2)subsequently through line 111, circuit terminal C and in parallelthrough solenoids 101 and closed switch 101s and through solenoid 105and closed switch 105s when switch 103s is open so as to bring stops 70sand 1 17s down against cams 130a and 132a to locate shutter panel 62 andbutterfly valve 3511 in the desired partially open position. If it isdesired that the heat from particular apparatus 16 being controlled beshut off instead of be at intermediate heat output, the aforedescribedportion l) of Circuit No. C7 need not be used and the homing units ofswitches 130 and 132 may be energized instead in that particular one ofthe 16 apparatuses 16.

The number of combinations available is nearly inifinite, and can beselected by the drying needs of element 12 for its wetness condition andspeed of travel in direction T. Hence, the heat output control meansincludes means responsive to the speed of travel of element 12 forcontrolling the plurality of apparatuses 16 so that different apparatus16 heat output combinations are provided. For example, since element 12can stand more heat when it is wetter burning or damaging element 12 iftoo much heat is applied after it becomes partially dry, heating means26 of apparatuses 116 in bank B2 on the downstream side of rollingsupport roller 24 may be adjusted to emit a lower infrared heat outputto run 12b in their heating zone than the upstream heating means inapparatus 16 in bank Bl to run 12:: so that wetter element ll2a in theupstream heating bank can be dried more rapidly but the dryer element12b in the downstream heating bank will not be burned or otherwise heatdamaged.

While fabric element 12 is laden with liquid, temperature control ofelement 12 is not critical because the latent heat of evaporation of theliquid makes it easy to maintain the temperature of element 12relatively close to the boiling point temperature ofthe liquid. However,after most liquid has been removed from element 12, maintenance of thiselement temperature is more difficult as may occur when processingofelement 12 requires a curing operation, additional heat treatment,etc. Fabric element 112, then in view ofits lower specific heat andsmall weight, can be maintained at uniform tempera ture (or at aselected and controlled rate of temperature change or final temperature)only by providing quick infrared energy level change in heating zone l6if element 12 stops or changes in speed,

Stepping switch 1136 provides modulating control to the infraredtransmission zone 69 sizes in shutter panel 62. Hence, the heat outputcontrol means thus comprises means for operating shielding means 62 tointercept the travel of more of the infrared emission portions in themore shielding positions and changes the heat output to heating zone 40independently of the residual heat in heating means 26. Hence, immediatechange in infrared energy level will be obtained by repositioningshutter blades 65, and if necessary, butterfly valve 35d to change theoutput of heating means 28.

It is desirable that the position of shutter slats 65 generally controlthe heat intensity in heating zone 60 and the shutter slats be onlypartially open then so that there will be immediately available moreinfrared energy from the heating means in the event more heat output isrequired. Then, no thermal lag or inertia will occur in the flowofinfrared heat as might occur ifthe shutters were fully open andinfrared output would have to be adjusted and controlled by onlybutterfly valve 35d.

Generally, thermal inertia of infrared heating means 26 prevents quickenough energy output change in response to the demands of the control.After the control demands a decrease in infrared output, reducing fuelto the heating means requires too long to respond. The present inventionovercomes this problem by permitting shutter slats 65 to decreaseimmediately the infrared transmission energy apertures or zones 69 inshutter panel 62 so that the heat intensity in heating zone 40 isindependent of the thermal inertia of the heating means.

Since piston 70p and stepping switch 13'!) are responsive to speed ofelement 12 and thus responsive to the temperature or heat buildup inelement 12, they form part of the heat output control means operativelyconnected to the shielding means 62 for moving shutter slats 65 in sucha manner as to maintain the desired temperature ofelement l2.

Panels 62 have numerous advantages given in the following numberedparagraphs.

First, each heating apparatus 116 has venetian-blind-type shutter panel62 permitting: (1) starting and stopping of web element 12 withoutdamaging element 312 by applying excessive heat thereto, (2) quickcontrol of the heat from infrared generators 31 to element 12 by either(a) closing slats 65 to protect element 112 when stopped against theresidual infrared heat in infrared generating heating panel 311 or toreduce the infrared heat applied to element 112 in heating zone as, or(b) having the infrared heating panel 311 on and subsequently openingshutter panel 62 to apply quickiy, or to increase, infrared heat toelement 12, and/or (3) maintaining stream 42 of high velocity gastraveling in contact with heated surface lFll of but there is danger ofelement 12 and prevented by shutter slats 65 from blowing out or coolingthe flame on gas-fired infrared heating panel 3ll.

Second, shutter panel 62 is especially adapted to uniformly treatelement 112 in a modulated manner uniformly across its width dimensionW. The infrared transmitting zones 69 between shutter slats 65 extendacross width dimension W and are generally of uniform rectangular size;gas stream 62 is uniformly distributed across width dimension W andtravels along direction T to uniformly process each portion of the widthW of element 12. Also, shutter panel 62 remains in the same position atall times between heating means 28 and heating zone 40; in contrast, asliding type, opaque curtain (instead of venetian-type-blind 62) wouldhave to slide between this position in front ofheating means 28 forblocking infrared transmission and an infrared transmission position toone side of heating means 26. Such sliding-type curtain would have thedisadvantages of over exposing some portions of element 112 and underexposing other portions of the infrared radiation during travel betweenthese positions, slowness in response in travel between the positions,and inability to throttle or modulate infrared transmission except on acompletely off or on ba sis.

Third, shutter panel 62 permits quick shutoff of infrared heat toheating zone 40, quick turn on of this heat, and accurate and infinitestep variation of this heat by quick and easy adjustment of the infraredtransmitting zones 69 sizes by a venetian-type-blind movement of shutterslats 65.

Fourth, shutter panel 62 prevents adverse effect on the flame energizedheating means 28 by flowing gas stream 42. Shielding means 62 orientsgas stream portions i2 close to and over element 12 outer surface F1 andaway from heating means 28 so as not to cool, or adversely affect,heating means 28. Shielding means 62 comprises a plurality ofvenetianblind-type shutter slats 65 lying in a zone extending generallyparallel to heating zone 40 with each shutter slat 65 inclined towardheating zone 40 in the direction of movement of gas stream 42 fordirecting the gas stream portions toward heating zone .10 and away fromheating means. 28. Inclination of slats 65 prevents bounce of portionsof gas stream 42 through infrared transmitting zones 69 of shutter panel62 and against heating means 26. Use of shutter panel 62 permits the useof extremely high velocity gas stream 42 without disturbance of theflame on heating means 28. Velocities as high as 6,800 feet per minuteat gas discharge nozzle 50 have been successfully used. It should beapparent that the highest practical gas stream velocity is desirablebecause it assures adequate cooling of shutter slats 65 when they areclosed and heating means 28 is operating at full infrared output,adequate cooling of element 12 to prevent heat damage thereto and tomaintain any desired temperature thereof, and efficient and rapidevaporation of moisture therefrom by removal of any vapor layerevaporated from element 12 so as to provide rapid drying and to enhanceefficient transmission of the infrared rays from heating means 28 toelement 12 in heating zone 46 by rapid and efficient removal of thevapor layer otherwise inhibiting infrared transmission. This evaporatedliquid vapor and removed heat is herein called the removed infraredgenerated heat products.

Fifth, shutter panel 62 desirably effects infrared generation andtransmission. As mentioned earlier, infrared heaters preferably have infront of their flame-carrying plate, or a mat a reradiating screen toincrease the burner efficiency and to assist in providing a uniformdistribution of infrared radiant energy in front thereof. As this screenreflects heat back onto the flame-carrying plate or mat, the plate ormat increases in temperature, and since infrared radiation is a functionof the temperature of the emitting source, better infrared radiation isobtained therefrom. Here, the grid of reflecting metal formed byparallel slats 65 of shutter panel 62 in front of infrared heater 32acts like a similar reradiating screen in front of the mat formaintaining its radiating temperature and to provide a more desirableinfrared radiation. Also, the angularity of slats 65 and the maintainedreflectivity of the aluminized steel construction of plate portion 65bof each slat 65 will permit slats 65 to reflect or bounce the infraredradiation from heating means 28 through transmitting apertures 69 ofshutter panel 62 to heating zone 40 even if the transmitting zones 69are only partially open, and even if heating means 28 cannot clearly seeelement 12 through zones 69. The multiple angles on each slat 65, causedby the three cold work breaks 65c, enhances this ability to reflect, orbounce through, infrared radiation. Also, it should be noted that anybounced through radiation will be generally uniformly spread across thewidth dimension W of element 12 and diffused along length dimension L touniformly process element 12 as it travels in direction T since the axisof oscillation of each slat 65 and the orientation of each cold workbreak is generally parallel to width dimension W. Also, the six angularsurfaces on plate portions 65b formed by the three cold work breaksstraddling each infrared transmitting zone 69 causes the infrared rayspassing therethrough to be diffused and reflected over a zone extendingsome length in dimension L on element 12 to minimize hot spots onelement 12.

Sixth, shutter panel 62 can be moved to the fully closed position whileheating means 28 continues to provide full infrared output withoutdamaging fabric element 12, whether it is stationary or still travellingin direction T, because gas stream 42, moving across the surfaces ofelement 12 and shutter slats 65, removes the infrared generated heatproducts therefrom to prevent shutter burnup and element 12 damage.

Seventh, there is an advantage in being able to shut transmitting zones69 in shutter panel 62 without turning off heating means 28 because mostline stoppages of travel of element 12 in direction T are of shortduration and the infrared heat is immediately available when infraredtransmitting zones 69 again open to provide immediate fabric element 12heat up and uniform processing.

TWO-PASS AND ONE-PASS POSITIONS Element 12 may make either two passes orone pass, or run, through drying tower 14. FIGS. 1 and 3 of the drawingsshow in solid lines the two-pass position having two passes or runs 12aand 12b over drive rolls 23, 24, and 23a and show the onepass positionhaving only one pass or run 12b partially in solid and partially indot-dash lines (to the right in FIG. 1 and to the left in FIG. 3) overdrive rolls 23, 24, and 24a.

Drying tower 14 can be rapidly and easily converted from the two passposition in FIGS. 1, 2, 4 and 7 to the one-pass position in FIGS. 1 and3. All of the apparatuses 16 in tier B2 in FIG. 1 can be moved fromtheir solid line position in FIGS. 1 and 3 to their dot-dash lineposition in FIG. 3 for processing element 12 in the one-pass positionover drive rolls 23, 24, and 24a in FIG. 1 by: (l) loosening andremoving all of the nutbolt units 160 and 16d in apparatuses 16 in tierB2 in FIGS. 1 and 2; (2) removing two of the straight duct sections 136in FIG. 3 from gas stream inlet duct 46 in each apparatus 16 in tier B2and replacing them with two angular duct sections 138, as shown indot-dash lines; (3) removing four reflector plates 74 and center wall76; 4) moving subframes 16a and 16b in all apparatuses 16 in Bank B2from their solid line to dot-dash line position toward element run 12ato move all heating panels 31, gas discharge nozzles 50, gas exhaustopenings 56, and shutter panels 62 in bank B2 into their dot-dash lineposition in FIG. 3; (5) attaching two modified reflector platesstraddling the ends of element 12 with each plate attached at oppositeends to a base member 64 on each shutter panel 62; and (6) inserting nutand bolt units 160 and 16d in each apparatus 16 in tier B2 in FIG, 2through appropriately located holes in subframes 16a and 16b, and thentightening these nut and bolt units to secure subframes 16a and 16b inthe dot-dash line position in FIG. 3 to provide the one pass position.

Hence, heating means 28 in tier B2, or in the downward run or pass 12bof element 12 over rollers 24 and 23a is constructed to move between thesolid line two pass and the dotdash line one pass heating positions inFIG. 3 toward element run or pass 12a over rollers 23 and 24 so that allof the heating means 28 in tiers B1 and B2 now simultaneously heatopposite generally parallel faces F1 and F2 of element 12 in run sincemachine 10 is now adjusted so that element 12 does not travel betweenthe heating means in its earlier downward pass 12b over rollers 24 and23a but now passes over rollers 24 and 24a. The gas moving means,including nozzles 50 and openings 56 in tier B2, are also constructed tomove with its associated heating means toward tier B1 between these twopass and one pass heating positions.

Each of these positions, the one pass and two pass positions, havecertain advantages mentioned in the next paragraphs.

The two-pass position shown in solid lines in FIG. 1 has the advantagesof: (1) processing element 12 in minimum height of drying tower 14, soas to minimize capital investment; (2) providing element 12 at leastpartial drying in upward pass 12a over drive rolls 23 and 24, andfurther heat treatment during its downward pass 12b over drive rolls 24and 23a; (3) providing twice as many drying apparatuses 16 in a givenheight dry ing tower 14 to permit finer adjustment of the heatdifferential between apparatuses 16 to provide better element 12processing; and (4) providing contra gas flow gas stream 42 indownstream run 12b (gas streams 42 going upwardly while element 12 goesdownwardly in direction T) to provide more rapid and complete dryingofelement 12in run 12b.

A one-pass position has numerous advantages when heating means 28 andgas streams 42 are face-to-face on opposite sides of element 12 in eachtier T. For example, if only one gas stream 42 were used and this struckonly one side of element 12, element 12 might be laterally deflected andlaterally flapped by this one gas stream 42 to put unnecessary tensionon fabric element 12, to distort the shape of gas duct 78, to moveelement 12 away from heating means 28, and/or to provide otherdisadvantages. This is not true when two apparatuses 16 are usedface-to-face in the one pass position. Then, fabric element 12 ismaintained substantially taut and planar against lateral deflection andflapping by the gas streams since this deflection and flapping isminimized by having the gas discharge means in each apparatus 16,including the two gas streams 42, symmetrically straddling element 12,and by having rolls 23 and 24 suitably driven to exert sufficienttension on element 12 between rolls 23 and 24.

There are other advantages in having two apparatuses 16 facing eachother at each tier, such as tier T3 in FIG. 1, with one apparatus 16 ineach bank B1 and B2. Then, these two heating apparatuses 16 are mountedwith their two heating zones 40 having sandwiched therebetween thegenerally coinciding opposite faces F1 and F2 of element 12 so that eachdries one of the opposite generally coinciding parallel faces of element12. This structural arrangement and coaction has a higher heating ordrying heat; simultaneously heats or dries both sides of fabric element12; more rapidly heats or dries fabric element 12; and requires noreflector (such as center wall 76 in FIGS. 1,2 and 7) behind element 12,such as would be necessary if only one drying apparatus in a one-passposition or if a two pass position were used. Such reflector may have ashort useful wear life if it gets tarnished or tends to melt under thehot infrared radiation heat.

Both single-pass and two-pass positions have certain advantages. Eightapparatuses 16 in bank B1 in FIG. 1 in tiers T1T8 arranged in seriesalong direction T of travel of element 12 have certain advantages. Eachof these apparatuses 16 has its own gas discharge nozzle 50 and gasexhaust opening 56 for generally uniformly processing width W of element12 in series arranged heating zones 40 as element 12 moves upwardly inFIG. 1 past these 8 series arranged apparatuses 16 in bank Bl. Each ofthese 8 drying apparatuses has its own vertically traveling gas stream42 formed from relatively fresh, dry, cool air at ambient conditionssucked in from outside drying tower 14 for its discharge nozzle 50 andhas water molecule saturated, or at least heavily laden, air(substantially raised in temperature) exhausted through exhaust fan 60by outlet duct 58 at the top of drying tower 14 so as to not inter- Zllfere with the flow of fresh, dry air into tower ll ll for dischargenozzles 50. Having eight separate, vertically arranged, gas streams l2is a substantial advantage over having a single gas stream 42 passingfrom the bottom to the top of tower M. This single gas stream would(after it traveled more than one tier in height) be too heavily ladenwith water molecules to provide an effective scrubbing action forremoval of evaporated water, be too heated up to provide an effectivetemperature control by cooling element 12, be too heavily concentratedwith water molecules so as to prevent effective infrared transmissionfrom heaters 32 to element 112, have lost its upward velocity so itwould no longer scrub off the water molecules or remove the convectionheat, not be able to be kept confined to surface F1 or F2 of fabricelement 112 because it would lose its upward velocity, and not be ableto be confined to a compact stream but would spread laterally and thusbe totally useless. The advantage of dividing a single gas stream intoeight separate se ries arranged gas streams l2 becomes more apparentwhen one realizes that the free vertical travel of each gas stream 42 ateach tier in FIG. 1 may be generally about eight feet vertically in thetypical installation while a single stream may have to travel about lOOfeet traveling the vertical heights of drying tower 1 1. Also, it ispossible by using the sixteen separate dry ing apparatuses 16 in dryingtower 14, arranged in horizontally opposed pairs and in eight seriesarranged pairs, separately to control the infrared heating action andflow of gas stream 42 in each component apparatus 116 to match theexisting and desired conditions of temperature and moisture removal fromelement 12 as it is progressively heated or dried as it moves throughtower 114. This would not be possible if a single gas stream were usedfor the whole height of tower M Also, it has been found during operationof tower M that the temperature of element 112 and the temperature ofthe discharged air at the top of each tier Tl-T8 can be controlled to beapproximately the same even though element 12 becomes progressivelydrier as it moves through tower 114,.

The invention may be embodied in other specific forms without departingfrom the spirit or essential characteristics thereof. The presentembodiments are therefore to be considered in all respects asillustrative and not restrictive with the scope of the invention beingindicated by the appended claims rather than by the foregoingdescription, and all changes which come within the meaning and range ofequivalency of the claims are therefore intended to be embraced therein.

What is claimed and desired to be secured by Letters Patent is:

I. An apparatus for heating fibers in yarn or fabric in a continuouslength element comprising:

a. a plurality of gas-fired heaters for tion;

b. means for moving a fiber element in heat exchange relationsuccessively past the heaters;

c. a shutter associated with each heater and disposed between eachheater and fiber element during normal operation of the heater forheating said element, each shutter having an aperture;

d. a plurality of slats mounted in the aperture of each shutter forrotation about parallel axes; and

e. means, responsive to movement of the fiber element in relation to theheaters, for rotating the slats of each shutter.

2. The apparatus of claim l, which includes sive to rotation of theslats of a shutter to a closed position where the slats are in alignedrelation parallel to the plane of said shutter, for moving a heaterassociated with said shutter in a direction away from said shutter.

3. The apparatus of claim 2, which includes means, responsive to closureof a shutter, for shutting off gas to a heater associated with saidshutter.

4-. The apparatus of claim 1, wherein the means (e) includes means formaintaining the slats of each shutter in a fully open position where theslats of each shutter are in parallel planes angularly disposed to theplane of the shutter when the fiber element is moving past the heaters.

5. The apparatus of claim l, which includes means for discharging gas,under pressure, into the space between the fiber element and eachshutter.

6. The apparatus of claim 5, wherein into the spaces in contacting,ment.

7. The apparatus of claim 6, wherein the gas is discharged at a ratesufficient to adversely affect normal operation of the heaters.

8. The apparatus of claim 1, wherein the means (e) includes means forrotating the slats of each shutter to a closed position, when the fiberelement stops moving.

9. The apparatus of claim 8, wherein the means (e) includes means formaintaining the slats of each shutter in a fully open position where theslats of each shutter are in parallel planes angularly disposed to theplane of the shutter, when the fiber element is moving past the heaters.

10. The apparatus of claim 9, which includes means for shutting off gasto a heater when the: slats of a shutter as sociated with said heaterare in a closed position; and means for moving a heater in a directionaway from a shutter associated with said heater, when the slats ofsaidshutter are in a closed position.

emitting infrared radiameans, responthe gas is discharged parallelrelation to the fiber ele' EETTEE STATES EETEET oEETEE fi'lll hflh'lfhEQRRETCTWN Patent No. 3 $3 3M Dated February 22 1972 Inventor(s) David ZTyson Edward E Hunter Willie Herman Best It is certified that errorappears in the above-identified patent and that said Letters Patent arehereby corrected as shown below:

C010 2 line 8 "therefore should read therefor g 33 "therefore should.read M therefor Cole n, line M9 "18'' should. read M 28 o Col 51, line15 "18" should read 28 0 (301., 9 line 2 should read 65' a Colt, 10 line.2 "62o should read 620 0 16 r" should read M M0 0 26 "62c" should read620 C01. 12 line 3'7, "62c: should. read M 620 m 57 62c" should read M620 O Col. 1% line "15f" should read. m 115i 69 "elimihete should read Melement ---0 C01.), 19 line l l- "(2" should read 65'0 u sisnm andsealed this 29th day Of August 1972' (SEAL) Attest: EDWARD MELBTGHEEQJRQROBEEKT (E'OTTSCHALK t ttesting Officer Gommlsslonetr of Paten FORM PO-1USCOMM-DC 60376-1 69 U.5v GOVERNMENT PRINTING OFFICE: I969 0-366-334

1. An apparatus for heating fibers in yarn or fabric in a continuouslength element comprising: a. a plurality of gas-fired heaters foremitting infrared radiation; b. means for moving a fiber element in heatexchange relation successively past the heaters; c. a shutter associatedwith each heater and disposed between each heater and fiber elementduring normal operation of the heater for heating said element, eachshutter having an aperture; d. a plurality of slats mounted in theaperture of each shutter for rotation about parallel axes; and e. means,responsive to movement of the fiber element in relation to the heaters,for rotating the slats of each shutter.
 2. The apparatus of claim 1,which includes means, responsive to rotation of the slats of a shutterto a closed position where the slats are in aligned relation parallel tothe plane of said shutter, for moving a heater associated with saidshutter in a direction away from said shutter.
 3. The apparatus of claim2, which includes means, responsive to closure of a shutter, forshutting off gas to a heater associated with said shutter.
 4. Theapparatus of claim 1, wherein the means (e) includes means formaintaining the slats of each shutter in a fully open position where theslats of each shutter are in parallel planes angularly disposed to theplane of the shutter when the fiber element is moving past the heaters.5. The apparatus of claim 1, which includes means for discharging gas,under pressure, into the space between the fiber element and eachshutter.
 6. The apparatus of claim 5, wherein the gas is discharged intothe spaces in contacting, parallel relation to the fiber element.
 7. Theapparatus of claim 6, wherein the gas is discharged at a rate sufficientto adversely affect normal operation of the heaters.
 8. The apparatus ofclaim 1, wherein the means (e) includes means for rotating the slats ofeach shutter to a closed position, when the fiber element stops moving.9. The apparatus of claim 8, wherein the means (e) includes means formaintaining the slats of each shutter in a fully open position where theslats of each shutter are in parallel planes angularly disposed to theplane of the shutter, when the fiber element is moving past the heaters.10. The apparatus of claim 9, which includes means for shutting off gasto a heater when the slats of a shutter associated with said heater arein a closed position; and means for moving a heater in a direction awayfrom a shutter associated with said heater, when the slats of saidshutter are in a closed position.